Completing the Circuit: STEM Education Activity

Fig.1

Fig. 2

I recently did an activity that demonstrated the flow of electricity. Not having much background knowledge on the subject, I found this activity to be very helpful. I still don't have all the information about electricity  that I would like to have, but I thought this activity would be great to include in a science lesson.

This is a very simple activity, and there are many follow-ups to it. 

This activity is designed to demonstrate the current of electricity flowing through a light bulb. After this activity, Students will be able to explain how to get a light bulb to light up and why a closed circuit is needed. A good connection to make is to a flashlight, since the elements of the activity are the same as those in a flashlight.

Materials:

• Flashlight light bulb (4.5v, 3amps)
• AA battery
• copper wire (I used copper wire in plastic casing with two jaw clamps attached to each end, but all you really need is the wire)

Background information:
In order for a light bulb to light up, there must be an unbroken flow of electricity. This means that the circuit must be closed in a circle. If the circuit is open, the electrical current will stop where the circuit ends.

Procedure:

Fig. 3

The goal for this activity is for the light bulb to light up. Ask the students to try it on their own. It may be a good idea for the students to have a little background information before beginning this activity.

Connect one end of the copper wire to the screw contact on the light bulb. connect the other end to the tip of the positive end of the battery (Fig. 3). Touch  the foot contact of the light bulb to the negative end of the battery (Fig. 4). It will light up. If it doesn't, you may need a larger battery or a light bulb with fewer watts.

Fig. 4

The wire conducts electricity from the battery to the light bulb. Electricity travels up one support wire, through the filament, and down the other support wire. This is how electricity travels in and out of the bulb. However, the electricity flow will stop at the end of the wire unless the circle is closed. When the bulb touches the other end of the battery, electricity can flow freely through the circle.

Follow up activities: Show the inside of a flashlight and ask students to name some of the elements. 

You can also make a flashlight if you have time and resources. HERE and HERE are some simple how-to on making flashlights. They're not in the form of classroom lessons, but I thought they would be pretty cool to do in the classroom.

Other sources:

TechEngineering: Completing the circuit